3D-printed Ti6Al4V femoral component of knee: Improvements in wear and biological properties by AIP TiN and TiCrN coating

Abstract

As patients are dissatisfied with the excessive weight of Co-based knee femoral components, it is an urgent need to reduce their weight without compromising the excellent mechanical properties. In the present study, femoral components of knee with Ti6Al4V alloy (86 g) or Co–Cr alloy (192 g) were printed by selective laser melting (SLM). In order to improve the mechanical properties and biocompatibility of 3D-printed Ti6Al4V, TiN and TiCrN coating layers were deposited on the surface of SLM Ti6Al4V using arc ion plating (AIP) system. The surface characterizations were analyzed by scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS), X-ray diffraction (XRD), contact angle tensiometer, and contact profilometer. The wear property, hardness value and corrosion resistance in phosphate buffered saline (PBS) were also investigated through vickers hardness, sliding wear test, electrochemical impedance spectroscopy and potentiodynamic polarization. The antibacterial capability and biocompatibility were assessed with Staphylococcus aureus and mesenchymal stem cells (MSCs) in vitro. Results illustrated that, after coating SLM Ti6Al4V with thin TiN and TiCrN layers, the hardness, anti-wear performance and corrosion resistance of SLM Ti6Al4V were significantly improved and became comparable to SLM CoCr. The TiN and TiCrN coated SLM Ti6Al4V also showed moderate antibacterial ability, and excellent biocompatibility in comparation with SLM Ti6Al4V and SLM CoCr.

Keywords

• TiN
• TiCrN
• Arc ion plating
• SLM Ti6Al4V
• Mechanical properties
• Biological evaluation